Henning: The fundamentals of watering houseplants

Posted: Friday, January 18, 2002

Do you remember learning how to speak or write? We make sure our children go to school, but unless we are forced, most of us will not take time to analyze many of our most basic activities. Writing this article, I am reminded of the voices of coaches from my youth preaching on the importance of fundamentals.

Frank

Henning

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Fundamentals always seemed to come the week after you lost -- I used to hate fundamentals. One of the most basic aspects of plant care is watering, another one of those fundamental activities that most of us take for granted.

Many plant problems will disappear with proper watering. The Surgeon General should require a label on every potted plant sold in America stating that improper watering is the leading preventable cause of premature plant death. But we would have to be careful, because we might experience a rise in teen-age gardening.

Proper watering begins with proper soil selection. All potting soil is not created equal. Look for a soil-less potting media that is sterile, porous, lightweight, and most importantly, one that will drain quickly. It is all but impossible to properly water soil that won't drain.

When filling pots with potting media leave yourself about a half an inch of head space between the soil surface and the rim of your pot. This small amount of headspace makes it easy to gauge how much water you are adding each time you irrigate. Another reason to leave yourself some headspace is to help keep your soil from washing out of pots and onto the floor.

When watering, try to develop a habit of checking plants on a regular schedule. If soil is allowed to get too dry, roots may be damaged from dehydration or fertilizer burn.

In order to reduce the incidence of disease try to water the soil without wetting plant foliage.

Water thoroughly every time you water. Apply enough water to moisten the entire soil volume, plus a little extra to leach soluble salts out of the container.

Indoor plants are usually placed on saucers to hold excess water that drains from the bottom of the pot. If the plant is left standing in this water, the moisture will be reabsorbed into the pot causing root rot, salt damage and generally poor performance.

To prevent this problem, discard any water in the saucer after each watering, or elevate the base of the container above the level of drainage water. One way to elevate pots is to spread a layer of gravel in the bottom of your saucer deep enough to keep the container above water.

Plant roots are usually in the bottom two thirds of the pot. For most plants, you don't want to water until this bottom two thirds starts to dry out. Therefore, you can't tell when to water by looking at the soil. For a 6-inch pot, stick your index finger about 2 inches into the soil. For smaller pots, 1 inch into the soil is the proper depth to measure. If you don't like to get your fingers dirty, you might try using a porous toothpick. In a short time you can probably determine when to water by simply picking up the pot. Water weighs more than air, so a dry potted plant will be lighter than one that has recently been watered.